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Mycobacterium tuberculosis (M.tb) is a multifaceted bacterial pathogen known to infect more than 2 billion people globally. However, a majority of the individuals (90%) show no overt clinical symptoms of active Tuberculosis (TB) and, it is reported that M.tb in these individuals resides in the latent form. Therefore, a huge burden of latently infected population poses serious threat to the human health. Inconsistent efficacy of BCG vaccine and poor understanding of latency-associated determinants contribute to the failure of combating M.tb. The discovery of DosR as the master regulator of dormancy, opened new avenues to understand the pathophysiology of the bacterium. Though the specific functions of various DosR genes are yet to be discovered, they have been reported as potent T-cell activators and could elicit strong protective immune responses. Rv0569 is a DosR-encoded conserved hypothetical protein overexpressed during dormancy. However, it is not clearly understood how this protein modulates the host immune response. In the present study, we have demonstrated that Rv0569 has a high antigenic index and induces enhanced secretion of Th1 cytokines IL-12p40 and TNF-α as compared to Th2 cytokine IL-10 in macrophages. Mechanistically, Rv0569 induced the transcription of these pro-inflammatory signatures through the activation of NF-κB pathway. Further, immunization of mice with DosR protein Rv0569 switched the immune response towards Th1-biased cytokine pattern, characterized by the enhanced production of IFN-γ, IL-12p40, and TNF-α. Rv0569 augmented the expansion of antigen-specific IFN-γ and IL-2 producing effector CD4

Dengue is a mosquito-borne disease caused by the four serotypes of the dengue virus (DENV 1-4). It is growing at an alarming rate globally, which could be partly attributed to the lack of an effective therapeutic regimen. Therefore, strategies for developing an effective vaccine have gained more significance in the given scenario. Failure of the existing live attenuated vaccine candidates to mount effective and broader protection against all the four serotypes of DENV has generated a new interest in exploring novel strategies for augmenting the efficacy of non-infectious, non-replicating subunit vaccines. In the current study, we employed a new strategy of encapsulating the immunodominant EDIII domain of Envelop protein of all the serotypes of DENV (1-4) into PLGA nanoparticles separately. All four nano formulations were physically mixed to develop a tetravalent nano formulation in combination with TLR agonists. Further, we examined its immunological efficacy using a mouse and

Light-responsive nanoliposomes are being reported to induce cancer cell death through heat and reactive oxygen species (ROS). Nanoliposomes (CIR NLPs) encapsulating a near-infrared (NIR) light-sensitive dye, IR780, and a bioactive chlorophyll-rich fraction of Anthocephalus cadamba (CfAc) were synthesized and characterized. These CIR NLPs, when activated by NIR light, displayed localized synergistic cancer cell death under in vitro and in vivo conditions. We demonstrated a NIR light-mediated release of CfAc in cancer cells. The bioactive CfAc was selective in causing ROS generation (leading to autophagic cell death) in cancer cells, while normal healthy cells were unaffected. An increase in the intracellular ROS leading to enhanced lipidation of microtubule-associated protein light chain 3 (LC3-II) was observed only in cancer cells, while normal cells showed no increase in either ROS or LC3-II. In vivo analysis of CIR NLPs in an orthotopic mouse model showed better anti-tumorigenic potential through a combined effect (i.e. via heat and CfAc). We reported for the first time induction of selective and localized, bioactive phyto fraction-mediated autophagic cancer cell death through an NIR light trigger. The synergistic activation of ROS-mediated autophagy by light-triggered nanoliposomes can be a useful strategy for enhancing the anticancer potential of combinational therapies.

Summary Obesity and obesogenic comorbidities have been associated with COVID‐19 susceptibility and mortality. However, the mechanism of such correlations requires an in‐depth understanding. Overnutrition/excess serum amino acid profile during obesity has been linked with inflammation and reprogramming of translational machinery through hyperactivation of amino acid sensor mammalian target of rapamycin (mTOR), which is exploited by SARS‐CoV‐2 for its replication. Conversely, we have shown that the activation of general control nonderepressible 2 (GCN2)‐dependent amino acid starvation sensing pathway suppresses intestinal inflammation by inhibiting the production of reactive oxygen species (ROS) and interleukin‐1 beta (IL‐1β). While activation of GCN2 has shown to mitigate susceptibility to dengue infection, GCN2 deficiency increases viremia and inflammation‐associated pathologies. These findings reveal that the amino acid sensing pathway plays a significant role in controlling inflammation and viral infections. The current fact is that obesity/excess amino acids/mTOR activation aggravates COVID‐19, and it might be possible that activation of amino acid starvation sensor GCN2 has an opposite effect. This article focuses on the amino acid sensing pathways through which host cells sense the availability of amino acids and reprogram the host translation machinery to mount an effective antiviral response. Besides, how SARS‐CoV‐2 hijack and exploit amino acid sensing pathway for its replication and pathogenesis is also discussed.

Immune cells sense and programme its cellular machinery appropriately to the environmental changes through the activation of cytoprotective adaptive pathway so-called the "integrated stress response (ISR)". However, the mechanisms implicated in ISR-induced protective responses are poorly understood. Here, we show that ISR activation by arsenite (Ar) results in suppression of IL-1β production in macrophages and inhibition of DSS-induced colitis in a murine model through a novel posttranscriptional and translation regulatory (PTR) mechanism. Ar triggers PTR events through eIF2α-phosphorylation, which results in the attenuation of active polysome formation leading to the accumulation of translationally stalled IL-1β mRNAs. Translationally stalled IL-1β mRNAs recruit RNA-binding proteins (TIA-1/TIAR), resulting in the formation of RBP-RNA complexes known as stress granules (SGs). The SGs bound IL-1β mRNAs might undergo degradation through induction of autophagy. Also, we show that Ar posttranslationally impairs processing and secretion of IL-1β by diminishing inflammasome activation. Altogether, this study unveils a novel mechanism of IL-1β regulation and further suggests that pharmacological activation of cytoprotective ISR pathway might provide an effective therapeutic intervention against inflammatory diseases.

Ulcerative colitis (UC) is a persistent inflammatory illness, which is clinically categorised as Inflammatory bowel disease (IBD), affecting millions of people worldwide. The precise cause behind the pathology of the disease remains unknown. However, the involvement of multiple factors including genetic predisposition, immunological deregulations, microbiota imbalance, and environmental triggers has been suggested. Amongst all these factors, the over-active immunological response reported in UC patients seems to be a promising target for therapy. Moreover, identification of gene signatures associated with disease onset and progression would help in better understanding of the molecular mechanisms involved in the disease pathogenesis. Here, we have conducted meta-analysis of gene expression profiles of UC patient microarray datasets accessible in public databases and further validated the in-silico findings in UC patients' blood samples. Our study reveals that UC pathogenesis perturbs expression of several inflammatory genes. In addition, we report a novel gene signature comprising of TIA1 (T cell restricted intracellular antigen) and TIAR (TIA1 related protein; also known as TIAL1), which were found to be significantly downregulated in UC patients. TIA1 and TIAR are RNA-binding proteins (RBPs), which function as a translational represser by binding to ARE sequences in the 3' UTR of mRNAs encoding inflammatory mediators including cytokines. Our findings demonstrate that deletion of TIAR using gene specific siRNAs in-vitro results in enhanced production of inflammatory cytokine IL-1β. In conclusion, the findings of this study reveal that down regulation of TIA1/TIAR genes could be responsible for UC associated inflammation. This study highlights the usefulness of the meta-analysis approach in the identification of unique gene signatures that might deliver mechanistic insights into UC pathogenesis and possibly assist in discovery of prognostic markers and therapeutic interventions.

Plant-derived active principles may serve as potent and cost effective alternative medicinal strategy for human ailments. Artemisia absinthium is a potent medicinal plant growing wild in Kashmir Hi...

Macrophages are prone to oxidative stress which can result either in severe damage to their function or even cell death. The present study was aimed to reveal the cytoprotective potential of Artemisia nilagirica (clarke.) extracts against tertiary butyl hydroperoxide (t-BHP) induced cell death and possible anti-inflammatory potential using RAW 264.7 murine macrophages. The extracts were shown to provide cytoprotective action in t-BHP treated cells via inhibition of lipid peroxidation, ROS generation and restoration of mitochondrial membrane potential. There was a significant change in the expression of genes for antioxidant enzymes in the cells which helped the cells to ameliorate the damaged biochemical machinery within cells. Furthermore, the extracts displayed a prominent downregulation of inducible nitric oxide synthase (iNOS) which led to a reduction of nitric oxide in lipopolysaccharide-treated RAW 264.7 cells that indicated the anti-inflammatory potential of these extracts. It was also foun...

The application of nanotechnology in vaccinology has fuelled rapid advancement towards the design and development of nanovaccines. Nanoparticles have been found to enhance vaccine efficacy through the spatiotemporal orchestration of antigen delivery to secondary lymphoid organs and antigen-presentation by Antigen Presenting Cells (APCs) synchronized with stimulation of innate and adaptive immune responses. Metal based nanoparticles (MNPs) have been extensively engineered for the generation of nanovaccines owing to their intrinsic adjuvant-like properties and immunomodulatory functions. Furthermore, mesoporous nanocapsules of late have attracted researchers due to their precise size and exclusive capacity to encapsulate a wide range of biomolecules and their sustained release at the targeted sites. Herein, we have designed a novel mesoporous ZnO nanocapsule (mZnO) having a size of ∼12 nm with an average pore diameter of 2.5 nm, using a surfactant-free sonochemical method and investigated its immunomodulatory properties by using Ova loaded mZnO nanocapsules [mZnO(Ova)] in a mice model. Our findings show that mZnO(Ova) administration steered the enhanced expansion of antigen-specific T-cells and induction of IFN-γ producing effector CD4+ and CD8+ T-cells. Also, antigen-specific IgG levels were enriched in both the serum and lymph nodes of mZnO(Ova) immunized mice. Further, we noticed a substantial increase in serum IgG2a or IgG2b levels and IFN-γ secretion in Ova restimulated splenocytes from mZnO(Ova) immunized mice, indicating that mZnO(Ova) skew Th1 type immune response. Overall, the uniqueness of mZnO nanocapsules in terms of the defined particle to pore numbers ratio (maximum of three cavities per particle) allows loading antigens efficiently. Given these features in combination with its immunomodulatory characteristics reinforces the idea that mZnO could be used as an effective antigen-adjuvant platform for the development of novel nano-based vaccines against multiple diseases.

The integrated stress response (ISR) is a homeostatic mechanism by which eukaryotic cells sense and respond to stress-inducing signals, such as amino acid starvation. General controlled non-repressed (GCN2) kinase is a key orchestrator of the ISR, and modulates protein synthesis in response to amino acid starvation. Here we demonstrate in mice that GCN2 controls intestinal inflammation by suppressing inflammasome activation. Enhanced activation of ISR was observed in intestinal antigen presenting cells (APCs) and epithelial cells during amino acid starvation, or intestinal inflammation. Genetic deletion of Gcn2 (also known as Eif2ka4) in CD11c(+) APCs or intestinal epithelial cells resulted in enhanced intestinal inflammation and T helper 17 cell (TH17) responses, owing to enhanced inflammasome activation and interleukin (IL)-1β production. This was caused by reduced autophagy in Gcn2(-/-) intestinal APCs and epithelial cells, leading to increased reactive oxygen species (ROS), a potent activator of inflammasomes. Thus, conditional ablation of Atg5 or Atg7 in intestinal APCs resulted in enhanced ROS and TH17 responses. Furthermore, in vivo blockade of ROS and IL-1β resulted in inhibition of TH17 responses and reduced inflammation in Gcn2(-/-) mice. Importantly, acute amino acid starvation suppressed intestinal inflammation via a mechanism dependent on GCN2. These results reveal a mechanism that couples amino acid sensing with control of intestinal inflammation via GCN2.

Rheumatoid arthritis (RA), a symmetric polyarticular arthritis, has long been feared as one of the most disabling forms of arthritis. Identification of gene signatures associated with RA onset and progression would lead toward development of novel diagnostics and therapeutic interventions. This study was undertaken to identify unique gene signatures of RA patients through large-scale meta-profiling of a diverse collection of gene expression data sets. We carried out a meta-analysis of 8 publicly available RA patients’ (107 RA patients and 76 healthy controls) gene expression data sets and further validated a few meta-signatures in RA patients through quantitative real-time PCR (RT-qPCR). We identified a robust meta-profile comprising 33 differentially expressed genes, which were consistently and significantly expressed across all the data sets. Our meta-analysis unearthed upregulation of a few novel gene signatures including PLCG2, HLA-DOB, HLA-F, EIF4E2, and CYFIP2, which were validated in peripheral blood mononuclear cell samples of RA patients. Further, functional and pathway enrichment analysis reveals perturbation of several meta-genes involved in signaling pathways pertaining to inflammation, antigen presentation, hypoxia, and apoptosis during RA. Additionally, PLCG2 (phospholipase Cγ2) popped out as a novel meta-gene involved in most of the pathways relevant to RA including inflammasome activation, platelet aggregation, and activation, thereby suggesting PLCG2 as a potential therapeutic target for controlling excessive inflammation during RA. In conclusion, these findings highlight the utility of meta-analysis approach in identifying novel gene signatures that might provide mechanistic insights into disease onset, progression and possibly lead toward the development of better diagnostic and therapeutic interventions against RA.

The Secret Life of a Vaccine Antigen-specific CD8 ÷ T cells play a central role in the adaptive immune response to viral infections and to cancer. Ravindran et al. (p. 313 , published online 5 December) studied the successful yellow fever virus vaccine YF-17D to gain insight into its mechanism of action. The vaccine activated the nutrient deprivation sensor, GCN2 kinase, in dendritic cells. In transgenic mouse models, GCN2 activation promoted autophagy and antigen cross-presentation, enhancing the virus-specific CD8 ÷ T cell response. The findings suggest an important role for nutrient availability and autophagy in vaccine efficacy, which could aid more successful vaccine development.

Immunological programing of immune cells varies in response to changing environmental signals. This process is facilitated by modifiers that regulate the translational fate of mRNAs encoding various immune mediators, including cytokines and chemokines, which in turn determine the rapid activation, tolerance, and plasticity of the immune system. RNA-binding proteins (RBPs) recruited by the specific sequence elements in mRNA transcripts are one such modifiers. These RBPs form RBP–RNA complexes known as “riboclusters.” These riboclusters serve as RNA sorting machinery, where depending upon the composition of the ribocluster, translation, degradation, or storage of mRNA is controlled. Recent findings suggest that this regulation of mRNA homeostasis is critical for controlling the immune response. Here, we present the current knowledge of the ribocluster-mediated post-transcriptional regulation of immune mediators and highlight recent findings regarding their implications for the pathogenesis of acute or chronic inflammatory diseases.

Blocking T cell co-stimulatory signals by anti-B7-1/B7-2 mAb is an attractive approach to treat autoimmune diseases. However, anti-B7-1/B7-2 mAb treatment is known to exacerbate autoimmune diseases through mechanisms not fully understood. Tumor necrosis factor alpha (TNF-alpha) and reactive oxygen species (ROS) also play important roles in determining the clinical outcome of autoimmune diseases. In this study, we demonstrate that the anti-B7-1 and the anti-B7-2 mAbs activate macrophages for higher induction of TNF-alpha and other effector responses such as bacterial cytotoxicity and production of ROS. Nuclear factor-kappaB (NF-kappaB) was found to be increased with anti-B7-1/B7-2 mAb treatment. Inhibition of NF-kappaB activity by over-expression of phosphorylation-defective I-kappaB alpha in anti-B7-1/B7-2 mAb-treated macrophages decreased TNF-alpha production. These data indicate that anti-B7-1 and anti-B7-2 mAbs can trigger innate-effector responses in macrophages by activating NF-kappaB-signaling pathway. Our results suggest that the B7 molecules are not only essential for induction of adaptive immune responses but also play roles in activation of innate immune responses.